fix(langgraph-checkpoint-sqlite): store channel deltas

[Pragnyan Ramtha (pragnyanramtha)]

Summary

• respect newVersions in SqliteSaver.put so SQLite checkpoint rows only store changed channel_values
• keep legacy full checkpoint writes when callers omit newVersions
• enable the existing checkpoint-validation delta storage conformance test for SQLite
• add a patch changeset for @langchain/langgraph-checkpoint-sqlite

Fixes #594.

Validation

• pnpm --filter @langchain/langgraph-checkpoint build:internal
• pnpm --filter @langchain/langgraph-checkpoint-sqlite build:internal
• pnpm --filter @langchain/langgraph-checkpoint-sqlite test
• pnpm --filter @langchain/langgraph-checkpoint-validation exec vitest run src/tests/sqlite.spec.ts
• pnpm exec oxfmt --check libs/checkpoint-sqlite/src/index.ts libs/checkpoint-validation/src/spec/put.ts .changeset/swift-sqlite-deltas.md
• pnpm exec oxlint libs/checkpoint-sqlite/src/index.ts libs/checkpoint-validation/src/spec/put.ts
• git diff --check

[changeset-bot]

🦋 Changeset detected

Latest commit: 4b8214c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@langchain/langgraph-checkpoint-sqlite	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@langchain/langgraph-checkpoint

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint@2408

@langchain/langgraph-checkpoint-mongodb

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint-mongodb@2408

@langchain/langgraph-checkpoint-postgres

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint-postgres@2408

@langchain/langgraph-checkpoint-redis

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint-redis@2408

@langchain/langgraph-checkpoint-sqlite

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint-sqlite@2408

@langchain/langgraph-checkpoint-validation

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-checkpoint-validation@2408

create-langgraph

npm i https://pkg.pr.new/langchain-ai/langgraphjs/create-langgraph@2408

@langchain/langgraph-api

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-api@2408

@langchain/langgraph-cli

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-cli@2408

@langchain/langgraph

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph@2408

@langchain/langgraph-cua

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-cua@2408

@langchain/langgraph-supervisor

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-supervisor@2408

@langchain/langgraph-swarm

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-swarm@2408

@langchain/langgraph-ui

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-ui@2408

@langchain/langgraph-sdk

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/langgraph-sdk@2408

@langchain/angular

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/angular@2408

@langchain/react

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/react@2408

@langchain/svelte

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/svelte@2408

@langchain/vue

npm i https://pkg.pr.new/langchain-ai/langgraphjs/@langchain/vue@2408

commit: 4b8214c

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[Pragnyan Ramtha (pragnyanramtha)]

After the base refresh, the only red check I see is Browser Tests / sdk-vue.

I checked the job log: the Vue test suite itself passed (103 passed), then Vitest reported an unhandled browser infrastructure error: Failed to connect to the browser session ... [chrome] within the timeout. The same browser suite passed on the adjacent refreshed LangGraphJS PRs, so this looks like a flaky Chrome/session startup failure rather than a SQLite checkpoint regression.

I tried to rerun the failed job/run, but GitHub rejected reruns without repository admin rights. The branch is current with main; all other checks are passing.

[Christian Bromann (christian-bromann)]

SqliteSaver serializes the whole checkpoint (including channel_values) into the single checkpoint BLOB and getTuple/list return it verbatim with no parent merge. Filtering channel_values by newVersions at write time, without a version-keyed blob table to reconstruct from on read, means reading checkpoint N returns only the channels that changed in step N — every unchanged channel from prior steps is lost.

This breaks real graph state: channelsFromCheckpoint rebuilds regular (non-Delta) channels purely from checkpoint.channel_values (emptyChannels), so a dropped channel becomes fromCheckpoint(undefined) → empty channel on resume/time-travel/getState.

The correct pattern is already in checkpoint-postgres: _dumpCheckpoint strips channel_values, blobs are stored keyed by (thread_id, ns, channel, version), and _loadCheckpoint/_loadBlobs reconstruct the full channel_values on read via channel_versions. SQLite has none of this.

CI is green because the un-skipped test only stores independent checkpoints and asserts each one's own delta — it never chains checkpoints and reads a later one back to verify full reconstructed state.

Suggested fix: add a version-keyed checkpoint_blobs table, strip channel_values from the checkpoint blob, upsert changed channels in put, reconstruct in getTuple/list from channel_versions, and handle migration of existing inline-channel_values rows. Also extend the conformance test to chain checkpoints and assert the full state on read. As a stopgap, revert to storing full channel_values and keep the test skipped rather than ship lossy persistence.

(Minor: newVersions? is optional here but required in the base class / Postgres.)